Fast idle

[Timbo2]

Hi everyone, just got back from a short drive and noticed the idle is sitting at about 850/900, as if the A/C was on, its not the fast idle switch and the A/C is off. When started the idle is normal for about 3 secs then goes up. Grateful for any suggestions.

 

[JohnfromUK]

Hi everyone, just got back from a short drive and noticed the idle is sitting at about 850/900, as if the A/C was on, its not the fast idle switch and the A/C is off. When started the idle is normal for about 3 secs then goes up. Grateful for any suggestions.

Mine does vary - mainly between around 700 and 900 rpm. I've always assumed it is something to do with all the superflous and 'unnecessary add ons' to do with meeting emissions regulations and helps to warm up catalysts and DPF stuff more quickly. Doesn't cause any driving problems, but I agree it can be irritating.

 

[Grimbo]

Could be the battery taking charge..... alternators will now "talk" to the engine ECU and up revs to increase output .... so many things on a modern vehicle can communicate.... and command an upping of engine idle speed....it's all on the CAN

 

[Timbo2]

Could be the battery taking charge..... alternators will now "talk" to the engine ECU and up revs to increase output .... so many things on a modern vehicle can communicate.... and command an upping of engine idle speed....it's all on the CAN

That's interesting Grimbo, earlier in the day I jump started a camper van stuck at the petrol station!

 

[Timbo2]

Seems to have sorted its self out.

 

[AdventureWagon]

1GD engine? Mine does this too depending on the AC clutch state and other stuff I assume. Its also normal for a manual 1GD to idle at 1200rpm when doing a DPF burn. Not sure why the auto doesn't do this perhaps because it'll fly away if you released the brake completely.